Motorcycle Repair: charging problems 81 honda 500d, volt ohm meter, head gaskets

Question
my bike has problems charging the battery while running the battery is new and the alternator is only putting out about 10 when it should be 13.5 should i cange the alternator or stator i dont know the name to the right piece i need?
thanks you sir
also how would i know if the head gaskets are blown


Answer
Mike, there are three parts that could cause the battery not to charge.  You can check the stator with a volt ohm meter.  The three yellow wires out of the stator should have equal resistance between them and no continuity to ground.  If that checks out, it's probably the recitfier/regulator. The rotor should be fine.  Those rarely are bad.

Regards
Rich